Starlight
by Cre Ookami
Summary: Special, different Luna is back with the Doctor, but she's having a hard time putting her time at Hogwarts behind her and piecing everything back together. And in the meantime, the Doctor's song is starting to end... Sequel to Moonrise.
1. Chapter 1

Here we go again.

Hello, everyone. If you're new, welcome. If you're old, welcome back. I'm pleased to tell you that the second installment of what someone once referred to as the Luna!verse will be filled with even more Luna, original plot, and even a few old friends.

A quick note for the new ones: I recommend going back to Moonrise and starting there, because otherwise the tale of Time Lady Luna and her adopted dad will probably make little sense to you.

There's more to say, but I'll save it for the end. In the meantime, here's a prologue, if you will, a re-introduction.

(Also, Starlight is mostly a working title and I will let you all know if that changes. If you have any ideas please, _please_ let me know. Thanks.)

Disclaimer: I own neither Harry Potter nor Doctor Who.

* * *

_The first time it happened they were in Pompeii._

* * *

There was ash and smoke and blind panic when the sky fell. Terrified men and women and children ran through the streets towards the water, away from the mountain of fire above them, but few would find safety there. Among them were three travelers: one human and angry, who begged them to find safety in the hills, one ancient and alien, who sought to escape the damage he had wrought, and one half-young and half-human, who followed the other two.

This was Luna.

She was not talking to the people. She was not ignoring them. She was watching, watching everything: the Doctor's stiff shoulders and guilty anger, Donna's tears and useless advice, the screaming men and women, the burning sky. It was not the first massacre she had seen. It was, however, the first she had seen her father cause, and although she knew about the Doctor's darker side she had never seen it personally. He did a good job acting the protective father. Especially when it included protecting her from himself.

She had been gone, though, and in that time he had become harsher, rougher around the edges. She had become rougher too, but that was because of captivity not separation: that was Janice's fault; Janice and her tricks and all the games the spider-woman had played with her mind. Now she was different, she was cracked and off-balance. Now the dark and powerful and inhuman parts of her existed together in a single cohesive subconscious that Luna liked to call the not-Luna, because that part of her had all her skills and knowledge with none of her morals or ethics. That part was something she liked to keep hidden away.

She liked to keep it hidden away. But that didn't mean she always could.

The trio of travelers reached a building, a house inside which the TARDIS was parked – their way out. Cowering against the wall were the home's inhabitants: Caecilius, Metella, Quintus, Evelina. All hoping for salvation. Caecilius calling out on behalf of his family. Gods save us, Doctor.

The Doctor was ready to leave them.

Donna was not.

Luna was conflicted, and out of the conflict, out of her father's guilt and Donna's sorrow, rose the warped moralities of the not-Luna, coming together to create a Luna that was powerful and didn't care about the consequences and wanted to end the suffering.

"I could do it," she said softly.

They heard her.

Donna was confused for a moment. "Do what?"

The Doctor understood. "No."

Donna looked between them, standing still in the middle of the collapsing room, Caecilius' family pressed against the wall. "You mean you could stop this? You could save them?"

"Luna you can't."

She stood tall. Challenging. "I can. You know I can; I have that power."

"Power, yes but not the right. It's a fixed point. You can't change it."

"So says a society of old, dead men who never participated in the universe but still claimed the right to shape it. They are dead; we are all that remains. We could stop it all, could save everyone and destroy the Pyroviles. We can help. _I_ can help. Why shouldn't I?"

"Because there are laws of time and space we cannot break. We have to uphold these laws for exactly that reason: because the rest of the Time Lords are not here to. That job falls to us now, and the moment we disregard that and start playing with time is the moment we give up on everything we have upheld for millennia. We become the biggest hypocrites of them all."

"But I could save them, Dad. Look at all this, all this destruction. I could save people. That's what you do, save people!"

She expected him to be angry, but his eyes were just sad. "I know, Lunette, but we can't. Think of the consequences. Reapers and chaos, fractures through time, ripples and fissures that would destroy thousands more. That's far more dangerous than letting the timelines run their course. You can see that. You know I'm right."

She seemed to sag a little into herself, and when she spoke her voice was small. "I know. But can't we save at least some of them? Please?"

The Doctor looked over her head at Donna, who was staring at him with a strange mix of sorrow and expectancy. And then, just once, she tilted her head towards the family staring at them with wide eyes.

"I think," he said, placing a gentle hand on her shoulder, "that we can manage that."

And so everyone piled into the TARDIS, heading for the safety of the hills, where Cacelius and Metella and Quintus and Evelina watched their city drown in ash. The Doctor and Donna joined them. Luna did not. She instead meditated, calming her mind and untangling the mix of Luna and not-Luna, like she had done before. It was harder this time though, to sequester her dark side away.

* * *

_The second time it happened they were dealing with a slave trade._

* * *

They were reaching the part of their visit when everything descended into chaos. The executives were searching for them, the Ood were rebelling, there was strange chanting, and Luna was running through the compound dodging bullets and rabid Ood alike.

In short, things were progressing as normal.

Luna ducked behind a corner and paused to catch her breath. Travels with her dad were generally far more conflict-ridden than one would have expected, but a compound full of rabid Ood was pushing it even for him. She was going to give him a stern talking to.

After she found him, of course. He and Donna had been separated from her when they slipped off to have a look at the Ood and Luna had hung back to talk to one of the visiting executives who had mentioned the 2238 Warlock's Accord. (It turned out he was talking about the Warlock Clan from Agamemnon VI and not the Earth-based warlock but it was an interesting conversation nonetheless.) So when the conference room was overrun by mad Ood Luna had been alone.

Much like now.

Mostly rested, Luna poked her head back around the corner, and recoiled a second before a gun spat rounds in her direction.

She poked her head back around to tell the goon to be careful, he might take someone's eye out, but she caught sight of the head of the business and one of the high-up scientists sneaking into a building, so she settled for waving a spell in the direction of the gunman, leaving him hanging from the nearest roof. With another flick of her wand slipped into warehouse fifteen after the sneaking duo. It could be interesting.

Warehouse fifteen, unlike the others (she assumed) held no Ood. Instead the door opened to a hallway, which led to some stairs, which led to a red-lit room underground. There was machinery, and a large cabinet, and a metal catwalk that ran lengthwise across the room, high above the floor. The businessman (What was his name? Hapvin? No, Halpen.) was ordering the scientist around, monologuing all the while. A sign of someone who was going to hurt people. Janice had done it, when they fought and the blood and hate and not-Luna had rushed around her head.

(That blood and hate and not-Luna simmered now, and Luna half-realized that and was half-afraid.)

"We should evacuate," the scientist was saying. His name was Dr. Ryder. "If we can get back to the rocket-"

Halpen scoffed, opening a cabinet. "No need. We've got this." He pulled something out of the cabinet – a detonation pack. "Always been an option. The advantage of a family-run business; my grandfather drew up the plans." He handed two to Ryder. "Place these along the outside. We're gonna blow it up. This thing dies, so do the Ood."

Ryder hesitated for a moment, then followed Halpen around the railing to blow up whatever was below. Luna, every curious, stepped forwards to see.

It was a brain. The Ood's brain, she assumed, a telepathic center of some sort to connect them. It was surrounded by ring of energy, a blue current enclosing it. And Halpen was going to blow it up.

No. She would not let him.

"Girl!" From across the room, Halpen caught sight of her. "What are you doing? How did you get in here?"

"Through the door, of course. I'm very interested in your plan to blow up the Ood brain."

He strode across the room. "First that Doctor, now you. How many times must I tell you people: I don't care what the Friends of the Ood have to say. This is my business and I'm running it how I see fit."

"You don't have the right to destroy their lives and home."

"They're mindless animals," Halpen waved off. "We're helping them; we're teaching them things. They didn't mind!"

"They've lived here all their lives; they don't know what a human is. How much of a monster a human is."

"That's a hefty accusation coming from you, girl. Are you so disapproving of your own race?"

Her voice was laced with something dark and alien. "You make the mistake of thinking me human."

Halpen regarded her for a moment. "Have it your way. Child or not, human or not, I won't mind shooting you." He pulled a gun from his jacket. "I've never shot anyone before. Can't say I'll like it. But then, today's not exactly a normal day. Who knows?"

Ryder interrupted then. "The pylons-" He coughed. Luna turned to him.

"The pylons?" she prompted, far lighter than her previous comment. He nodded.

"I'm one too, you see. FOTO. The pylons are what's keeping the Ood docile, keeping them enslaved. If we can free the telepathic center..."

"The Ood will be free," Luna concluded. "Can you turn it off?"

"No, I don't know the codes. I've lowered the barrier to the minimum though." He turned to Halpen. "You never should have given me access."

"Dr. Ryder," Halpen said, lowering the gun momentarily. "You disappoint me." Then he turned and picked Ryder up, forcing him over the railing. Ryder flailed for a moment and tumbled over the side, falling into the brain, which slowly absorbed him. His screaming became muffled as he disappeared. Halpen turned back to Luna as Ryder disappeared. "Where were we?"

"You killed him," she said, blank.

"Yes. I'll kill you next. Dreadfully sorry, but you should have kept out of it."

That was, of course, when Donna and the Doctor entered, led by Halpen's personal Ood. Three things happened in quick succession.

First, Halpen, in his surprise, set off his gun. Second, the Doctor and Donna dropped to the floor to avoid the ricocheting bullet. Third, Luna lunged forward to grab the gun. They wrestled for a moment, until Luna wrenched the gun from his hand and turned it on him. Halpen backed away.

"Alright then. You can go." He smiled nervously. "I won't tell anyone. Go ahead. Tell your activist friends everything. Oh wait. This compound is brimming with rabid Ood, and I have this entire building ready to blow. I admit, it'll be a loss, but at this point I'm willing to risk it."

"We're not here to threaten you," the Doctor said from behind picking himself up off the floor. "Just to stop this. Luna, put the gun down."

Luna hesitated. But shooting him would get them nothing (except maybe some personal satisfaction). So she carefully put the gun down and slid it away from all of them.

But the warehouse was still prepared to detonate and the pylons were still blocking off the Ood and turning them crazy, and both they and Halpen needed to be taken out no matter what her dad said, so Luna (and perhaps a little more than just Luna) made a split second decision. She lunged forward and grabbed him.

"Luna, Luna no," the Doctor said behind her, but Halpen was already following Ryder over the side. Luna, unlike Halpen himself, had better aim, and instead of the brain he crashed into one of the pylons. The thing sparked and the circle of energy dissipated. The detonators beeped. Luna drew her wand and waved them off.

Everything was quiet for a moment. Luna stood at the railing. Donna and the Doctor stood behind her. The Ood brain pulsed, free. The detonators clicked off.

Below them, Halpen groaned.

"See? He's alive." And just like that she was fine again, the darker side of her slipping away as if she hadn't just thrown a man halfway across a room to what might have been his death.

Afterwards the Ood spoke of the Doctor-Donna, and praise, and the end of the Doctor's song. They did not promise to sing Luna's praise. They spoke in fear of the dark inside her.

Luna shared that fear quietly. She pushed the darkness further away. That would not help, though. It was becoming part of her.

* * *

_The third time it happened was when the Doctor was kidnapped by a Wirrn hive._

* * *

The first hint that something wasn't right was that he was late. Not that in and of itself that occurrence was particularly problematic – the Doctor followed plans like his companions followed directions (which is to say, not at all). So Luna and Donna shrugged and settled down to wait.

Four hours later, it was obvious something was more than just a little wrong.

"He did say to stay put," Donna said when Luna prompted an expedition to find him.

The Time Lady raised an eyebrow in response. "What sort of companion are you? Martha was ready to run off all the time. Sarah too; she told me all sorts of stories about it."

Donna scowled. "I hate bugs."

Luna just shook her head and dragged her out of the cupboard they were hiding in. Outside 14th century Prague was overrun by giant bugs (and the Plague, but that was a different matter). As luck would have it, the two wasted no time running into them. Literally.

Which was probably the quickest way to find the Doctor.

"Luna! Donna!" His hands were tied up, and he was grinning like a child. "There you are! What took so long?"

"Donna doesn't like bugs."

"Technically they're extra-terrestrial arthropods."

"They've got six legs and an exoskeleton," Donna said. "That's a bug in my book, Spaceman."

"You humans and your quaint labels," a Wirrn clicked at them, and for the first time Luna looked at the six-foot insectoid aliens scattered around the room. The one who spoke stood in the middle as the other Wirrn moved around him. "We will broaden your minds."

The Doctor's grin slipped away. "I told you," he said, suddenly solemn, "you can't just hatch larvae in living human beings. This is a class five planet, and is protected by the Shadow Proclamation. I'll help you find another world to colonize, one that will sustain you, but you can't stay here."

"We have already begun our colonization, Doctor. It is too late to end it." He hesitated. "I am sorry."

"Call back your troops, take the ones you've infected and leave. I'll help, I promise."

"It is too late," the Wirrn repeated. He assessed them for a moment. Then: "Take the adults to be fertilized. Leave the girl-woman."

"What?" Donna demanded. "Sorry, sunshine, but I am not going to be your living incubator."

Luna spoke over her. "No, you're not taking him away. Not again!" She wrenched herself free from the alien holding her, struggling to reach the Doctor.

"Take them out of here," the Wirrn ordered to the others sharply. "Let me deal with the girl-child."

Luna could faintly hear her father's voice over the scuttling of feet and the Wirrn's clicking speech as they gave each other orders, but the words weren't clear. Then they were gone, and Luna was alone with the Wirrn. She turned back to him slowly.

"Don't you dare hurt him. Either of them." Underneath her anger, taking advantage of her panic, the dark bloomed. She barely noticed. She barely minded.

"They are participants in the creation of a new world. I do not think your Doctor will contest that. Even in the stories, he is one who grants the gift of life."

"Have you heard the other stories? About the time he destroyed his own people, about the time he drowned the last Racnoss? Have you heard the Dalek's stories? Do you know what they call him?" Her smile was predatory. "They call him the Oncoming Storm. The Destroyer of Worlds. You are threatening the only home he has left. The only family. Tell me you're not just a little frightened."

The Wirrn clicked at her. "He is indisposed. By the time he can do any of the things you threaten, he will be useless. An empty vessel. We have nothing to fear."

"I'm his daughter," Luna told the Wirrn. "Perhaps you should reconsider."

The Wirrn clicked twice, and told the others around him, "I've changed my mind. Get rid of the girl-woman."

Luna smiled, vacant and hard, and drew her wand. "Too late."

The Doctor and Donna escaped fifteen minutes later when their guard kneeled over and died. The Wirrn-infected humans around the city were dead as well. In fact, every Wirrn who had come to Earth, egg, larvae or adult, was lying somewhere, dead.

Luna sat in the middle of the dead, in the middle of the room, tiny and fragile. The Doctor knelt next to her, silent. Donna looked away.

"I didn't mean to," she said quietly. "I just didn't stop."

Outside that room, the unsuspecting citizens of Prague burned the remains of the Wirrn with the rest of the wasted, unwanted, Plague-infested corpses.

* * *

_By then, Luna realised this was not something she could hide away. By then, Luna understood that Janice would not just go away, that it would continue to haunt her._

_By then, Luna knew she needed help._

* * *

This is definitely a little less happy than Moonrise. Janice is gone, but the repercussions will be hanging around. Luna's going to have a hard time growing up. And the Doctor's song is growing closer and closer to ending in the meantime.

I have to warn you, I'm pretty busy and still getting back into the swing of things, so don't expect too much too quickly. I'll update when I can, but this is a work in progress and it'll take a while. Rest assured, though: this is my baby, and I will not abandon it.

But chaos and scheduling aside, it's great to be back. This is going to be a fun ride. I hope you'll stick around for it.

Reviews, as always, are welcome.


	2. Chapter 2

Apologies for the lateness of this chapter. I'm working on it. I promise.

Disclaimer: I own neither Harry Potter nor Doctor Who.

* * *

There is a room in the TARDIS known as the Zero Room. Nothing from the world outside can get in. It is totally isolated, free of the chaos of the rest of the universe. The Time Lords used it originally to help with unusually difficult regenerations. Luna used it now to try and calm her mind.

It didn't help. Trying to catch the dark within her was like trying to catch smoke and pour it into a bottle: impossible. And yet she continuously came back, trying again to catch it and lock it up so it wasn't something she had to deal with anymore. So it wasn't a part of her anymore.

"Luna."

She looked up.

The Doctor stood there, framed in the open door. Luna made to stand up, but the Doctor waved her back down. He stayed in the doorway.

"You can come in," Luna said. He hesitated in the door for a moment longer, then moved to sit next to her. The door hissed shut behind him, leaving the room full of heavy silence. The peaceful, open calm from earlier was gone. Luna shifted, uncomfortable. The Doctor noticed.

"Luna-" he said again.

"Don't," she told him. "I don't want to hear pity. I can see it already."

"It's not pity, Luna."

"I don't care. You can't fix it. I know; I've tried. One of these days you will have to lock me up, like you did to her." Like you do to all of the threats you can't stop. And Luna was definitely a threat he would not be able to stop.

"Lunette, I would never-"

"You would, if you thought you had to. If it was a choice between me and a civilization, between me and a planet, if it was like the Wirrn again, you would have to stop me. I know you would."

"No," he said, taking her hands in his. They were shaking. "No, Lunette. I would help you."

"How can you help me when you can't even tell when it's going to happen?"

"What do you mean?"

Luna twisted her hands together. "I can always feel it coming, but by then it's already there and I can't do anything... Surely you can feel it?"

"Through the bond? No. Not like before." He paused. "Maybe it's Janice."

"Maybe I'm just growing up."

She was growing up; she wasn't the tiny girl he had found in his TARDIS all those years ago. Luna had lost track of her age over the years spent with the Doctor, with the timelines and the tangled web of gold. She was eighteen, maybe. She felt like two hundred. Her eyes were old, and that was the age that really mattered. Her body was that of a young woman, and her eyes were ancient and alien.

The Doctor sighed. "I wanted you to be a child for a little longer."

"I travel with you. I could never be a child for long." Silence reigned for a long moment, and Luna sighed. "It was supposed to be over. Once Janice was gone, I was supposed to be okay again. But I'm not."

"I know, Lunette. I'm sorry."

"I don't want sorry. Sorry doesn't help me, Dad."

"Which is why I have something besides just sorry," he said, reproachful, and she ducked her head in apology. "I have a story to tell you."

"A story?"

He nodded and stood up, offering her a hand. "Yes. But how about we move somewhere a little more comfortable. I don't know about you but I could use some tea."

* * *

They ended up in the same kitchen they always talked in, the one they always ended up at ever since the very beginning when Luna had been young and curious. She was still curious, but age had tempered that.

Luna sat up on the counter while the Doctor busied himself with hot water and mugs and tea. Once they were both settled with cups of earl grey (hot), Luna prodded him with a toe. He looked like he was far away. Luna brought him back.

"You said you had a story," she said.

"So I did." He stirred his tea and leaned back against the counter opposite her. "It's not a particularly nice story though. Well, it's not much of a story in the first place. More of a few words of wisdom. Father to daughter, all that."

She looked at him over the rim of his mug and he sighed.

"Once upon a time I was in a very similar position to you," he said. "Well, without most of the backstory, but the chaos, the dark and all that power- that was the same.

"The Time Lords aren't- we're not- we don't interfere. Didn't. But I wanted to; I wanted to see the universe so I stole a TARDIS and ran away. I was always planning on bringing her back." He patted the counter next to him lovingly. "I just never really got the chance."

He shook his head, running a hand through already-mussed hair. "No, wait, I'm getting off topic. I ran away. Yeah. And when I stepped out into the universe I found I could do so much. All that life out there to be protected. And I was ready to protect it. But I made the mistake of choosing one or the other. And when I met someone in the wrong, well. I was powerful. It was never a problem, fixing them permanently. I took lives because it was my right.

"And then I got worse. I got clever, I manipulated people into taking their own lives. It was easy to start. And hard to stop."

I know, she wanted to say. I've seen you do it. She didn't. Instead she asked, "So how did you stop?"

He smiled wryly. "I started traveling with them. All my companions, always amazed by the scope of the universe. To remind me how to be human."

She stared at him, skeptical over the rim of her tea mug. "Does it really help?"

He half-shrugged. "Mostly. Control comes with practice and age and finding something to hold on to. And I'm going to help you do that."

"But how? I can't stop it. You can't stop it. Donna's completely useless – nothing against Donna of course. How are you going to make it go away?"

He put his mug down and crossed over to her, pushing himself up onto the counter. His embrace was warm and comforting and familiar. "You can't make it go away, Lunette," he said softly. "I would that you could, but you just can't. It doesn't work like that. You have to figure out how to work around it, how to refuse it. You're gonna do it, though. I know you will."

She leaned into his shoulder. "I wish none of it had happened, Dad."

"Me too, Lunette." She could feel the press of his lips against her hair. "Me too."

* * *

Afterwards, when the tea was cold and they were done talking they wandered down innumerable hallways, emerging finally in the console room. They fiddled with the controls, challenging each other to fly closer to that star, slip between the pair of planets revolving around each other, jump years by increments of five, ten, fifty. Each time Luna's turn came around her father sat back and watched her with a tiny contemplative frown creasing his forehead. Luna never asked why – she didn't want to disrupt the atmosphere. It was old and familiar and comfortable.

Donna wandered in hours later complaining about the size and scope of the TARDIS and how bloody difficult it was to find them. The Doctor waved it off and instead invited her to give the old girl a spin.

"You've got to be kidding me," Donna said.

"No, really. Here, your right hand goes on that lever there-"

Luna stood back and watched as the Doctor hovered over Donna who in turn flipped switches on his orders.

"Careful, careful," he muttered, almost to himself. Then, louder, "Left hand! Left hand down- no, down!"

"Oi, shut it, I know what I'm doing."

"He's afraid you'll crash into the 80s," Luna offered, ever-helpful.

Donna rolled her eyes. "What, it's not like I'm gonna put a dent in 'em."

"Well someone did," the Doctor sulked. And then quieted, because there was a phone ringing somewhere among the mess of electronics. Luna shifted a few odd bits and pieces and found it – an old mobile from 2000s Earth. Martha's.

Luna answered it over Donna's comment about the phone ("Since when do you have a mobile?").

"TARDIS, Luna speaking."

The voice on the other side was fuzzy but unmistakable. "Hello? Luna? It's Martha. D'you think you guys could stop by? We need a bit of help. I'll brief you when you get here."

"It's Martha," Luna said to the Doctor, covering the phone. "She'd like us to stop by." He was already programming coordinates.

"We're on our way," Luna told her. "Don't hang up – we'll trace the signal."

"Thanks. I think your dad'll enjoy this one."

Flying with the Doctor at the helm was little better than Donna's driving. Luna said as much.

"Oi," twin voices echoed, and Luna smiled faintly. Maybe her dad was right. She could do it. She would be fine.

Or maybe not.

Time would tell.

* * *

Sorry for the time it took to post this. Things have been hectic. But I just finished nanowrimo and therefore have some lingering creative inclination.

Thanks to everyone who has read, followed and reviewed. So glad you're sticking around.

Reviews are, as always, welcome.


	3. Chapter 3

I have excuses but I'm sure you don't care to hear them. At least I got this done, right?

Disclaimer: I own neither Harry Potter nor Doctor Who.

* * *

They landed almost-smoothly in an alley in London. The Doctor exited first – just a precaution, he said – and Luna followed him. Martha grinned widely at her over the Doctor's shoulder.

"Luna!"

"It's nice to see you again, Martha."

"I was just telling your good-for-nothing father you don't visit enough."

"Tell me about it," Donna broke in, stepping out of the TARDIS. "There's never anywhere to buy groceries and he refuses to stop off at Tescos."

Martha looked back at the Doctor. "Didn't take you long to replace me I see."

"No no no, don't be like that," he replied. "Martha, Donna. Donna, Martha. Don't start a fight. I can't bear fighting."

"Sure," Donna muttered, shaking Martha's hand. "I've heard all about you. He talks about you all the time."

"I dread to think," Martha answered with a wry twist of her mouth.

"No, good things. Nice things. Really nice things."

Martha groaned. "Oh God, he's told you everything."

"Oh, you got over it fast Luna says. Anyways, who's the lucky man?"

The Doctor blinked between them. Luna grinned. She had missed Martha. "The who?"

Donna rolled her eyes. "She's engaged, you prawn." Martha wiggled her left hand, sunlight glinting off the silver engagement ring.

"So?" Luna prompted, interested.

"Tom, Tom Milligan. He's in paediatrics, working out in Africa right now. And yes, I know, I've got a doctor who disappears off to distant places. Tell me about it."

"Congratulations," Luna said.

"Is he skinny?" Donna asked. The Doctor was still trying to follow the conversation.

"No," Martha replied, blushing a little. "He's sort of... strong."

"He-" Donna jerked a finger over her shoulder at the Doctor. "-is too skinny for words. Try to hug him you get a papercut."

Martha laughed. The Doctor scowled.

"I'd rather you two were fighting."

"No you wouldn't," Luna told him.

"No, I wouldn't," he agreed.

The radio on Martha's hip beeped and the woman's voice on the other side of the line was tinny. "Dr. Jones, report to base please."

She turned away from the travelers, pulling the walkie talkie from her belt as she walked away, the joking, friendly aura falling away like water. "This is Dr. Jones; Operation Blue Sky is a go." The trio hurried after her. "I repeat, Blue Sky is a go."

On the street jeeps full of soldiers trundled down the road, followed by trucks full of equipment. As they approached the building on the left – a large, low, slate-grey warehouse-sized factory with half a dozen giant sliding doors – men in red berets began to pour out of the trucks and into the building. One of them spoke into a megaphone, voice ringing over the clunk of boots and chaos of movement.

"Unified Intelligence Taskforce, raise barriers now. Leave your safeties on, lads. It's non-hostiles."

The sliding doors rose slowly, and inside factory workers reacted in panic. A commander ordered them to lie down, trying to give orders and pacify them at the same time. A few soldiers were pulling out handcuffs. Luna, the Doctor and Donna watched it all unfold in shock.

Next to them Martha was issuing orders of her own. "Greyhound Six to Trap One. B Section, go, go, go! Search the ground floor, grid pattern Delta."

"What are you searching for?" the Doctor asked, frowning at the military might. He remembered UNIT, and UNIT was not this.

"Illegal aliens," Martha replied shortly, pausing barely a moment before she ran off, issuing orders as she went. The soldiers worked steadily, red berets moving like ants around the building. Luna looked after her with the same frown as her father. She remembered Martha, and Martha was not this.

Next to her Donna put the feeling into words. "Is this what you did to her? Turned her into a soldier?"

The Doctor just shook his head and watched her melt into the crowd, eyes old and sad. Luna stood next to him, feeling exactly the same.

* * *

It didn't take long to secure the base, and soon jeeps full of men and women in lab coats with computers came rolling in. Martha found them then, hair slightly mussed and sporting a lackey in a fetching red beret. "We're setting up a field base," she said by way of explanation, not waiting for a question. "It's a temporary thing. Come on, I'll introduce you to the Colonel. They're all dying to meet you."

"I wish I could say the same," the Doctor muttered, staring at the gun Red Beret was wearing. Martha gave him a patented Martha Look and he slumped and followed her, Donna in tow. Luna slided up next to her as they wound through the trucks and jeeps and soldiers and scientists.

"So you're a proper doctor now," she said.

Martha grinned. "Yeah. UNIT rushed it through given my 'experience in the field.'"

"You deserve it."

"Thanks, Luna." Martha elbowed her playfully. "And look at you, all grown up. How tall were you last time I saw you? You must have grown a foot."

"Don't start acting like my aunt," Luna begged. "I can't stand aunts."

"I know what you mean," Martha agreed. "Still. It's so great to see you all again. Promise me you'll catch me up on everything that's happened."

"Yes." Luna thought about Janice and Hogwarts and Martha's easy military motions and her eyes darkened and her voice was heavy. "I guess it has been a while."

Martha saw something, or heard it in her voice maybe, but they were at the door of a truck twice as big as any of the others and there wasn't time to ask about it because Donna and the Doctor were right behind them and Red Beret was opening the door for them. Martha looked at Luna and her eyes said, later.

Inside the truck was a bank of computers. Men and women with badges and lab coats and guns at their hips typed furiously and spoke quietly into tiny, sleek headsets. Martha led them past all of the hustle and bustle to a balding man with light hair and dark eyes and a decorated green uniform. He stared at them down a long nose.

Martha stepped forward. "Operation Blue Sky is complete, sir. Thank you for allowing me the lead." The man nodded once, and Martha shifted over to gesture to the Doctor, still staring around at the equipment. "And this... this is the Doctor." He looked up at the mention of his name. "Doctor, Colonel Mace."

"Sir." Mace saluted. The Doctor grimaced.

"Oh, don't- don't salute."

"But it's an honor sir." His voice was as strict as his uniform. "I've read all the files. Technically speaking you're still on staff. You never resigned."

Donna looked around the truck then back at the Doctor with a quirked eyebrow. "What, you used to work for them then?"

"Yeah, back in the seventies- or was it the eighties? It was all a bit more homespun back then, though."

"Times have changed, sir," Mace told him.

"Okay, that's enough of the sir," the Doctor said flatly.

Martha interrupted what sounded like a budding argument. Luna caught her eye and smiled a tiny thank-you smile. "Come on though, Doctor. You've seen it. You were on board the Valiant." The corners of his mouth turned down and she hurried ahead. "We've got massive funding from the UN all in the name of Security. It's just a precaution."

"A modern UNIT for the modern world," Mace said.

"What, and that means arresting ordinary workers? In the streets? In broad daylight?" Donna demanded. The Doctor's eyes stopped darkening. He knew as well as Luna did that once she got started nothing would stop her. "It's more like Guantanamo Bay out there," she continued, lecturing Mace like a schoolteacher. "Donna, by the way. Donna Noble, since you didn't ask. I'll have a salute."

Mace looked to the Doctor, almost confused. The Doctor controlled his grin and nodded. Mace saluted.

"Ma'am."

Donna took it graciously. "Thank you."

"And since it appears my manners have deserted me I must ask your apology as well," Mace said, turning to Luna. "You are?"

"Luna," said Luna. "His daughter."

"Honored," said Mace. She didn't get a salute, but that was fine by her. She didn't need one.

"So," said the Doctor once the formalities were taken care of. "Tell me what's going on in the factory."

Mace's hands went behind his back as he started reporting. "Yesterday fifty-two people died in identical circumstances across the world, in eleven different time zones. Five am in the UK, six am in France, eight am in Moscow, one pm in China-"

Luna understood. "They all died simultaneously."

Mace nodded. "Yes. Fifty-two deaths at the exact same moment. Worldwide."

"And how did they die?" questioned the Doctor.

"They were inside their cars," said Mace unhelpfully.

Martha was more succinct. "They were poisoned. But I checked the biopsies: no toxins. Whatever it is left their systems immediately."

"So what have the cars got in common?" Donna asked.

"Nothing. Different makes, models, years. Except one thing: they were all outfitted with ATMOS." Martha pointed out the door they came in. "And this is the ATMOS factory."

The Doctor stared at the door and then back at Martha. "Yeah, good. Just... what's ATMOS?"

Donna rolled her eyes. "Oh, come on spaceman, even I know that. Everybody's got ATMOS."

"Dr. Jones, would you care to take the Doctor and his associates into the factory? I'll be along momentarily."

"Yessir," Martha said. "Come on, I'll explain."

* * *

The Doctor stared down through the grid of the catwalk to the nearly empty factory floor below. "So there's no carbon emission? None at all?"

"Then why is it called the Atmospheric Emissions System?" Luna asked. Martha could only shrug.

"It's a great deal," Donna told them. "Comes with sat-nav and half a dozen shopping vouchers if you invite a friend."

"And this is where they make it," the Doctor half-asked.

"Yeah," Martha said. "And then they ship it worldwide. One of seventeen factories total. This is the central depot, actually."

The Doctor looked at her. "And you think it's alien." It wasn't a question.

Martha nodded. "I think so, yeah. I mean, I've seen a lot of alien and Earth, and I can promise you it's not Earth. Way too far advanced. Maybe a hundred years from now, but here? Now? It's got to be alien."

The Doctor stared for a moment longer. Then: "Alright then. If Martha Jones says it's alien it's good enough for me."

Martha grinned a grin the Doctor could be jealous of and led them on to an office at the far end of the factory.

* * *

The office was small, empty except for a few binders on the desk and an ATMOS device laid out on a table in the middle. Colonel Mace stood next to it at attention. The Doctor's eyes glanced over him and fell on the pile of technology, eyes lighting up like Christmas had come early. "This is it?" he asked.

"This is it," Mace confirmed. "Laid bare. ATMOS can be wired into any make and model of car ever produced."

"You must have checked it before it went on sale," the Doctor argued.

"And we didn't find anything," Martha replied. "That's why I thought we should bring in an expert."

The Doctor fished through his pocket for a moment then pulled out a pair of glasses. "Really?" he asked, perching them on his nose and staring at the mess of wires on the table in front of him. "Who'd you get?"

"You, Dad," Luna said when everyone else just stared at him.

"Oh. Right. Me. Good." He was already totally engrossed with the ATMOS unit. Over his shoulder he gestured for Luna to join him, and the pair bent over mess of tech with gusto. Mace and Martha left after a moment, heads close together. Neither the Doctor nor Luna noticed them leaving, too engrossed with the ATMOS device.

"It's fairly terrestrial," Luna said, poking through wires and transponders and disconnected cables.

"Advanced but Earth-based, I agree. Though the core design..." He trailed off, pulling cords out of sockets to peer deeper into the device.

"But why would aliens be so keen on cleaning up the atmosphere?" Donna asked over them.

"Very good question," said the Doctor.

"Maybe they want to help?" she asked, half-hopeful. The Doctor paused long enough to stare at her.

"The thing is, there are eight hundred million cars on earth. Just imagine if you could control them."

"You'd have an army," Luna concluded. The Doctor nodded.

"Exactly."

"But clearly it's native in origin," Luna continued. "This is all Earth-based technology."

"Except that it's too advanced to be here naturally. In a few decades, maybe, but now, well..."

"You suspect aliens?" Donna asked.

"There's definitely something off here," the Doctor confirmed. "I'm not sure what it is, yet, but I'll figure it out."

Colonel Mace chose that moment to return with Martha in tow. He stared for a moment at Luna and the Doctor as they fussed with the device, paying absolutely no attention to him. Finally he cleared his throat.

"Well?"

"It's basically an ionizing nano-membrane carbon dioxide converter," the Doctor replied after a moment. "Which means ATMOS does exactly what it's supposed to do – filters the CO2 at molecular levels."

"We know about that, Doctor." Mace's voice was impatient but he didn't so much as twitch. "What's it's origin? Is it alien?"

"Not even a little," the Doctor said. "It's decades ahead of its time though." Mace leaned in closer to look and the Doctor stood upright, finally giving the man his full attention. Mace stopped short, surprised at the look on the Doctor's face. "Look, d'you mind? Could you stand back a little?"

Mace's expression cooled. "I'm sorry, have I done something wrong?"

"You're carrying a gun," said the Doctor, just as cool. "I don't like people with guns hanging around me, alright?"

"If you insist," the colonel stated, turning sharply and exiting the room. Martha watched him leave. Luna ignored it, busying herself fully with the machine. Better to focus her mind there than on all the ways the possible threat that Colonel Mace was could be neutralized before he had a chance to use that gun. That wasn't something she wanted to think about. That wasn't something she wanted to be a part of her.

So she focused on figuring out what exactly it was that made ATMOS so unnatural. Find something to hold onto, her dad said. She would hold on to the puzzle. That would work.

When she ascended from her brain fog her dad was speaking, the quiet buzz of conversation resolving into words.

"People with guns are usually the enemy in my book. You seem quite at home." It wasn't quite accusing, but it was close. Donna was gone, Luna noticed. For just a moment it was as if Martha had never left them, as if they were still traveling, before the Master and Janice and everything bad that had happened.

"If anyone got me used to fighting it was you," Martha returned.

"Oh right, so it's my fault." He deliberately turned away from her, pulling the sonic on the ATMOS device.

"Well, you got me the job," Martha pressed on, refusing to let him run away from the conversation. That was good, Luna though. Martha was good for him. She always had been, even when she was utterly besotted, before she understood his story from before her. "Besides, look at me."

He didn't turn the sonic off immediately. Luna put a hand next to his. "Dad."

He thumbed off the sonic.

"Am I carrying a gun?" Martha asked, gesturing at herself. Luna watched the conversation unfold with quiet interest. This was the first real conversation between the two since Martha had walked out. (How long had it been? A year? Three? Time was always so hard to follow linearly.) Watching people interact was always a good way to read them; the Master had taught Luna that once. (So had her dad, to be fair, but the Master's lesson were always more permanent.) Luna watched the exchange and read between the lines, read how things were different. She wondered what someone like Donna, unfamiliar with both of them, might see. She knew what she saw.

"No," the Doctor answered finally. "Suppose not."

"It's alright for you," said Martha gently. "You can just come and go, but some of us have to stay behind. So I've gotta work from the inside, and by saying on the inside maybe I stand a chance of making them better."

"Yeah?" The Doctor smiled briefly. "That's more like Martha Jones." A peace offering.

"I learned from the best," she returned, accepting.

"Well..." the Doctor shrugged, drawing it out in his familiar way. His normal way, as if everything had fallen back in place. Luna agreed that it had, as much as it was possible.

"Oi!" Donna interrupted the moment in typical Donna fashion, crashing in without any hint of tact. "You lot. All your storm troopers and your sonic – rubbish. You should have come with me."

"And where have you been?" the Doctor asked her. Behind her Colonel Mace joined them, looking almost unwillingly interested. Perhaps the force of Donna's exuberance drew him in. She had that kind of personality.

"Personnel," Donna said. "That's where all the really weird stuff's happening – in the paperwork. Cause I spent years working as a temp and I can find my way around and office blindfolded, and the first thing I notice is an empty binder."

"What's missing?" Luna asked.

"Sick days," Donna proclaimed proudly, showing off the empty binder. "Hundreds of people work here and there's not one sick day. No flu, hangover, not even a measly shopping trip. Nothing. Not ever. They don't get ill."

"That can't be right," Mace interrupted, taking the binder and looking it over as if she had missed something. She hadn't.

"You've been checking the buildings. Should've been checking the workforce." Donna grinned.

"I can see why he likes you," Martha mused, almost to herself. "You are good."

"Super Temp," Donna offered.

Mace gave up and snapped the binder closed. "Doctor Jones, set up a medical post. Start examining the workers. I'll have them sent through."

Martha nodded and gestured to Donna. "C'mon. You're good at this; give me a hand." The two exited, heads bent together. The Doctor looked worried for a moment, but then Luna asked Mace a question and he returned his focus to the matter at hand.

"Who invented ATMOS?" she asked. Mace looked at the machine with a sour twist of his mouth.

"Luke Rattigan himself," said the colonel, and there was no mistaking the distaste there.

"And who would that be?" the Doctor asked. Mace started at them for a moment.

"Follow me. I'll show you."

* * *

He led them back to a temporary office in the back of a lorry, going straight to a computer monitor and pulling up a file. The Doctor and Luna crowded in behind him.

"Luke Rattigan, child genius. Invented the Fountain Six search engine when he was twelve. Millionaire overnight. Now he runs the Rattigan Academy, a private school for students handpicked from all over the world."

"A hothouse for geniuses," the Doctor mused. "Wouldn't mind going there."

Mace looked at him over his shoulder. The Doctor shrugged. "I get lonely."

"What about me?" Luna pouted in fake hurt. She didn't mean it, of course. Geniuses were always so interesting. Even the crazy ones. She should know.

"Well," the Doctor shrugged. "You won't want to travel with your old man forever." There was something more melancholy than expected in his voice, and Luna immediately dropped the subject. She didn't like the tone.

"I'll come with you," Mace said as they exited the traveling base. The Doctor raised an eyebrow at him.

"No. I want to talk to Luke Rattigan, not point a gun at him."

"It's ten miles outside London," Mace argued. "How are you going to get there?"

"Get me a jeep," the Doctor offered.

"According to the records you travel by TARDIS," Mace replied stiffly.

"Yeah, but if there's a danger of hostile aliens I think it's best I keep a super-duper time travel machine away from the front lines."

"I see," said Mace after a moment. "You do have weapons you choose to keep hidden." He considered it, then called out, "Jenkins!"

A soldier nearby snapped to attention. "Sir?"

"You will accompany the Doctor and his companions and take orders from him."

"I don't really do orders," the Doctor broke in. Mace ignored him.

"Any sign of trouble you declare a code red. Understood?"

"Yes sir," Jenkins replied, brisk.

"Sir," Mace saluted the Doctor sharply.

"I said no salutes," the Doctor grouched.

"Now you're giving orders," Mace pointed out with the barest hint of humor. He turned on his heel and left. The Doctor frowned after him.

"You're a bit cheeky," he grumbled to the retreating back. That was where Donna found them.

"There you are," she grumbled. "Never where I bleeding left you. You'll wander off and get lost one of these days."

"Hey," Luna said, affronted. "What do you think I'm here for."

"Oh, sorry, didn't see you there."

"Yes, yes, sorry," the Doctor overrode them. "You're here now, though, good. We're going to the country. Fresh air, geniuses, what else could you ask for?"

"I'm not coming with you," Donna said. "I've been thinking. I'm sorry, I've got to go home."

The Doctor's face fell instantly. "Oh. Really?"

"I've got to."

"Well, if that's what you want," the Doctor said, hesitant. Luna frowned.

"For good?" she asked. Donna looked between them.

"What? No, not for good. I've just got to visit, tell them where I'm going. You didn't think-" She looked between them. "You dumbos."

Luna shrugged. "It's a perfectly valid question."

"Great, big, outer-space dumbos."

"Technically I was born here," Luna argued, and the Doctor just shrugged, helpless. Donna rolled her eyes. "I give up. C'mon, you can give me a lift. To the country via Chiswick. Let's go, hurry up."

"Ready to go sir," Jenkins said. Then, after considering a moment, "Ma'am." They climbed into the jeep.

"Honestly," Donna muttered as they left the compound. "Dumbos."

* * *

It's better to beg forgiveness than ask permission, right? In which case, I heartily hope you excuse the lateness of this update. Life's a crazy train.

I've got the next chapter already written, though, so rejoice in the knowledge that the next update will be relatively prompt.

And if there's anyone left reading let it be know that reviews are, as always, welcome.


	4. Chapter 4

Don't even say anything.

Disclaimer: I own neither Harry Potter nor Doctor Who

* * *

The sign on the main road read Rattigan Academy, sharp letters colored in fresh white paint against the dark wood. The country road was empty except for the UNIT jeep stalled next to the open gate that led onto the property. The Jeep's three passengers looked through brick fence posts to the green campus beyond.

"Turn left," ATMOS ordered.

"UNIT's been watching Rattigan Academy for ages," Jenkins said, revving the engine to turn past well-trimmed hedges. "It's all a bit Hitler Youth: exercises at dawn and classes and special diets."

"One question," the Doctor said. "If UNIT thinks ATMOS is a bit dodgy..."

"How come we've got it in the Jeeps?" Jenkins laughed. "Tell me about it. They're fitted on all government vehicles. We can't get rid of them unless we can prove something's wrong. Drives me round the bend."

Around the corner the main building came into view. The Rattigan Academy was an old manor house at the outskirts of London, a feat of architecture from a bygone age, all brick walls and gravel paths and sprawling grounds. Carefully Ross parked the Jeep along the front drive.

"You have reached your final destination," ATMOS told them as they exited the car. Luna looked around in interest. It wasn't like a public school, like the one she'd been at in 1969, or the sprawling castle that was Hogwarts. Rattigan Academy was somewhere in the middle, imposing and also a little bit average. From around the corner of the house a pack of students came running around the corner in matching red sweatsuits. Some of them, Luna noted, were younger than she was. This was a school she might have gone to, had things played out differently. A science place instead of a magic place. She could see echoes in time.

"Is this Phys Ed?" the Doctor asked, bouncing almost as much as the students. "I wouldn't mind a game of footie."

At the front of the group a boy in grey sweats peeled off. He was tall, dark-haired, walked with a self-assured swagger that left no doubt that this was Luke Rattigan. Barely older than Luna and nearly as smart, if everything UNIT said was true. Behind him the other students filed inside. "You must be the Doctor," Rattigan said, smile thin and sounding wholly self-assured in his intellect. "Your commanding officer phoned ahead."

"Oh, I haven't got a commanding officer," the Doctor waved off. "Haven't you?" Rattigan smiled again, just as thin, and looked over the Doctor's shoulder to Luna and Jenkins. "Oh," the Doctor said, making a show of remembering his manners. "This is Ross. Say hello."

"Afternoon, sir," Jenkins greeted dutifully.

"And you?" Rattigan asked, turning to Luna.

"Luna," she replied, offering a hand. Rattigan shook it, and for a moment the gold around him was alight with memories of making secrets and the promise of a choice. Luna returned his smile, thin and careful. He wasn't quite a threat, but there was something in his shadow, and Luna hated puppets with masters in shadows.

"I assume you want to see inside," Rattigan said as she stepped back. "I'll give you a tour. All of the students are busy." Implicating that they were interrupting, and Rattigan clearly wasn't happy with that. Luna didn't really care.

Inside the house was nearly as impressive as the grounds outside. Arched ceilings, thick rugs, walls covered in intricate wooden paneling and paintings that probably deserved to be in museums. The Doctor paused in the foyer and took a deep breath.

"I can smell genius," he said with gusto. "In a good way."

Rattigan scowled slightly and led them through to a room every bit as overwrought and decorated as the rest of the house. But what was in the room was far more impressive – technology and innovation to rival the creative output of the planet. The Doctor looked like Christmas had come early. Luna understood the feeling.

Students were bent over projects, uninterested in the visitors even as the Doctor peered down over their shoulders. There was single-molecule fabric and gravity simulators, and vaguely recognizable bioforming software scrolling across a computer screen. Luna wandered through the room, staring at innovation as she went. Along the back wall a boy and girl about her age fiddled with the parameters a nano-tech steel construction machine.

"Set the frequency four nanometers higher," Luna offered under her dad's hyperactive babbling ringing through the room. "The metal ions will vibrate in sync."

They looked up, surprised she would talk to them, but Rattigan was busy with the Doctor and Luna was waiting patiently for them to try it, so the boy at the controls twisted a dial and input a number sequence and the machine hummed quietly, far smoother and softer than the rattle it had been making a moment ago.

"Thanks," he said. His partner asked, "Do you have any other tricks?"

"Well," Luna considered. "The Cheveran have – will have – a similar machine, except they used – use – will use a copper cable jack instead of the steel one because the metal is-"

"Luna!" her dad interrupted from across the room, gesturing out the door where Luke and Jenkins were waiting. Luna smiled, apologetic, and hurried over to them. Luke led them up three sets of stairs until they reached his quarters at the top story.

"You're smarter than the average UNIT grunts, I'll give you that," Rattigan said once the door was closed. The Doctor looked affronted.

"He called you a grunt," he said to Ross. Then, back at Rattigan, "Don't call Ross a grunt, he's nice. We-"

"This place," Luna broke in, dragging her father back on topic. Not that he wasn't running through a million scenarios in his head that very minute – Luna knew her father very well – but the quicker they dealt with this the quicker they were back in the TARDIS, away from all these potential threats and victims. Luna didn't like being grounded for long, not after Hogwarts. It made her anxious. Too many enemies and nowhere to run. "It's a little different, isn't it?"

"What does that mean?" Rattigan asked them, biting back a heavy sigh. The Doctor sobered up.

"We were thinking," he said, "what a responsible eighteen year old. Inventing zero-carbon cars, saving the world."

"It takes a man with vision." He didn't sound proud; he sounded aggravated. Tense.

"Mmm," the Doctor hummed. "Blinkered vision. Cause ATMOS means more people driving, more cars, more petrol. Which means?"

"Oil's gonna run out faster," Luna answered for him.

"Exactly. Your ATMOS system would make things worse."

"Yeah, well," Rattigan said quickly, word's almost tripping on their way out. "That's a tautology. You can't say ATMOS 'system' cause ATMOS stands for Atmospheric Emission System so you're saying Atmospheric Emission System system. Do you see, Mr. Conditional Clause?"

Luna didn't know what he was talking about, but the Doctor clearly did. "It's been a long time since someone's said no to you, isn't it?" He asked, voice gentler by far than it had been since they arrived. Rattigan scowled, looking less and less like one of the world's millionaires and more and more like Luke, an eighteen-year-old kid.

"I'm still right though," he argued.

"It's not easy being clever," Luna said into the big, almost-empty room. "No one else sees the patterns and the answers. They're all so slow."

"Yeah," Luke agreed slowly.

"And you're on your own," Luna continued, knowing that he was, knowing exactly how he felt being the clever genius among all the normal people, the strangers who couldn't understand and therefore didn't care.

"Yeah."

He wanted to turn away, she could see it in his eyes, but she had him caught fast. "I hated playing the puppet for all the tiny men. How do you stand it?"

"Sorry, what?"

"Nothing," the Doctor broke in, pulling an entire ATMOS device out of one of his bigger-on-the-inside pockets and giving Luna a careful look over Luke's head. She scowled, ugly and out-of-place, and let it go. Rattigan blinked, clearing his vision.

The Doctor kept talking as if nothing had happened. "There's no way you invented this by yourself. It's Earth technology, yeah, but it's like building a cell phone during the Renaissance. Actually, no, I'll tell you what it's like. It's like finding this thing in someone's front room." He tossed Jenkins the ATMOS unit and strode across the room – the very large, very empty room – to a thing in the corner that Luna had half-noticed when they had first entered and ignored in favor of examining Rattigan. Now she focused as her dad pointed it out. It was large, unwieldy and ugly and out-of-place in the big empty room. And Luna found herself thinking it did look somewhat familiar.

"Why?" Jenkins asked. "What is it?"

"It just looks like a thing, doesn't it? People don't question things. They look at it and go, 'Oh, it's just a thing.'"

"Leave it alone," Luke ordered sharply, looking almost frightened.

"Me," the Doctor continued, wholly content to ignore Rattigan. "I make these connections. And to me this looks like-" He found a button and pressed it with glee, and his last few words were cut off as he blurred for a split-second and then disappeared.

"Dad!" What was he doing, activating a teleport without knowing the destination. He could get someone killed doing that. Himself, for example.

But he was back before she was halfway across the room, eyes bright and running the minute his feet solidified enough to hit the ground.

"Time to go," he grinned. "Luke, you better come with us." But the teleport was humming to life again, something appearing on the open pad. Luna drew her wand, shorting out the machine's controls with a whisper of magic, but the teleport had already done its job and the Sontaran was already in the room.

Which was surprising, actually. Because Sontarans were the kind of space-faring race that avoided subterfuge like the proverbial plague. They faced their enemies head on, even if winning was more a move to mutually assured destruction than an actual victory. On one hand Luna could count all the occasions in known history that Sontarans had used hiding and proxy puppet wars over a straight, simple attack. It never ended well. Luna did not put her wand away.

"Sontaran!" If the Doctor was worried or unsettled by the abnormality of the events he did a masterful job of hiding it. "That's your name, isn't it?" The Sontaran – short and round and sheathed entirely in armor, as all Sontarans were – paused for a moment, gait stuttering to a stop in the middle of the room, the gun on his back half-drawn. "How did I know that, eh? Fascinating, isn't it. Worth keeping me alive."

Jenkins was not so interested on utilizing curiosity as a survival method. He drew his gun, aiming at the alien, speaking well-memorized words. "I order you to surrender in the name of the Unified Intelligence Taskforce."

The Doctor gently lowered his arm, bringing the gun back down. After a moment he stepped up to Luna and placed a hand on her arm. She refused to lower the wand.

"He's dangerous," she said softly, staring at the alien soldier over her father's shoulder.

"He's curious," he replied, staring at her intently. "You can't begrudge him his curiosity."

"He's a threat."

"And so are you. Put it away, Lunette. We don't need threats here."

Unhappy, she did as he ordered, contenting herself with the knowledge that should something go wrong she could be armed in seconds, and that there were dark secrets of combat that she barely understood hidden deep inside her mind. He stared at her for a moment longer, assessing, and then stepped back. His next words were addressed to the Sontaran.

"The copper bullets won't work, will they?" he asked, gesturing to Jenkins' gun. "Cordalaine signal's exciting them."

"How do you know so much?" the Sontaran asked, voice gruff through the helmet.

"Well," the Doctor shrugged, and he didn't answer the question.

So the Sontaran turned to Rattigan while the Doctor wandered the room. "Who is he?"

Rattigan shrugged. "He didn't give us his name."

"Why are you hiding?" Luna demanded, arms crossed, voice hard and deadly soft. "This isn't Sontaran behavior. Stopping bullets before they're fired, using teenagers, refusing to show your faces, that is no way for a warrior to act. Shame on you."

"You dishonor me!" the Sontaran roared at the accusation.

"Then show yourself," Luna challenged him.

"I will look into my enemy's eyes," he agreed, shifting the catch on his helmet and carefully pulling it away so the world could see his face – his round head, his small eyes, his scowl. Next to her Jenkins gaped.

"Your name?" the Doctor asked from behind them. Luna itched to pull her wand.

"General Staal of the Tenth Sontaran Battle Fleet," answered the alien soldier dutifully. "Staal the Undefeated."

"What happens when someone defeats you?" Luna asked lightly. Staal growled.

"It looks like a potato," Jenkins said, mouth finally catching up with his brain. "A baked potato. A talking baked potato."

"Now Ross, don't be rude," the Doctor admonished him stepping forward. He had a tennis racket in his hand. "You look like a weasel to him." From one of his infinite pockets a tennis ball appeared, and he bounced it experimentally a few times. "Sontarans are the finest soldiers in the entire galaxy. Fearless, strong, all that good stuff. Entire race dedicated to a life of warfare. A clone race grown in batches of millions, with only one weakness-"

"Sontarans have no weakness!" Staal protested loudly, hands reaching towards the gun. Luna watched him carefully.

"No, it's a good weakness," the Doctor assured him. Rattigan was staring at it all, incredulous.

"I thought you were supposed to be clever. Only an idiot would provoke him."

"Don't worry, he knows what he's doing," Luna assured the teenager.

The Doctor continued as if nothing had happened. "The Sontarans are fed by a probic vent on the back of the neck. That's their weak spot, which is why they always have to face their enemies in battle. Isn't it brilliant?" He grinned a crazy little grin at the ingenuity of the universe. "They can never turn their backs."

"We stare into the face of death," Staal proclaimed with solemn pride.

The Doctor bounced the ball again, and Luna could already see where it was going, could see a thousand different ways it could turn out. Carefully she prodded Jenkins back towards the door, away from the Doctor and Staal and Rattigan and whatever mess was about to go down.

"Yeah?" the Doctor asked above it all. "Well stare into this!" His aim was perfect, and the tennis ball bounced off the racket, off the teleport and hit Staal dead center in the probic vent. He staggered and fell, gasping. The Doctor was already herding everyone out of the room, but Rattigan broke away and ran back to the Sontaran. They didn't wait for him.

* * *

The Jeep started malfunctioning almost immediately after they climbed into it. The first to go was the radio, and then the wheel. Jenkins fiddled with every button within arm's reach as the car drove itself off the road. It did no good. ATMOS had full control of the vehicle.

"Turn left," the machine ordered, steering them towards the river approaching far more quickly than anyone liked. Jenkins tugged the wheel right but nothing happened.

"I've got no control," the soldier said for the third time.

"It's wired through the entire car," Luna said, shifting around the flooring in the backseat. "I can't turn it off."

"And the doors are dead bolted shut," the Doctor finished, thumbing his sonic uselessly for emphasis. "I can't stop it."

"Turn left," ATMOS ordered again. In the front window the river got closer very quickly

"Is it going by itself?" Luna asked, almost to herself. "Or is it just contradicting our orders?"

The Doctor jumped on the idea. "ATMOS," he asked, "are you programmed to contradict my orders?"

"Confirmed," the machine stated.

"You'll ignore anything I say?" he asked, just to be sure.

"Confirmed."

"Then drive to the river," he ordered as they reached the beach. "Drive straight into the river. Drive, drive, drive!"

And instead of speeding up either further the car stopped, jolting them all forwards.

"Turn left," ATMOS ordered. "Turn right. Left. Right." The locks disengaged and all three jumped out of the car. ATMOS got louder, and higher as it continued. "Right. Left. Left. Left."

"Get down," the Doctor ordered when it started to whine, high pitched and incessant and worrying. The three ducked down along the side of the road as the car sparked, and then ATMOS went silent. The Doctor poked his head up, frowning. "That's it?"

When it exploded he was the only one who singed an eyebrow.

* * *

An hour of walking and a particularly grouchy cabby later they arrived at Donna's house in Chiswick. The Doctor rang the doorbell with the heavy air of a man who had hitchhiked from Glasgow to Cardiff. Luna reminded him gently it hadn't even been all the way across London. He had only scowled and pressed the bell harder. Donna opened the door moments later.

"You would not believe the day I'm having," he said without preamble. Behind him Jenkins and Luna made faces at each other.

"I'll requisition a vehicle, sir," Jenkins offered quickly.

The Doctor waved him away. "Anything without ATMOS. And please don't point your gun at people."

He wandered halfway down the street to make a call. Luna half-contemplated joining him, but Donna was coming out of the house and leading the Doctor to the car on the street and there was someone inside calling out to them and someone had to make sure everyone behaved because she had learned a long time ago that leaving Donna and her dad alone together for extended periods of time could be a recipe for disaster.

That said, she would have loved to find some place in the TARDIS to curl up with a book and forget about all this stress and the fact that they all could have died twice so far that morning and how painfully difficult it was not to just draw her wand and wipe the Sontarans out of existence for threatening her homeworld and her father. But she could be better than that. She would be better than that, because her dad knew she could be and there was nothing she hated quite as much as disappointing him.

"Is it him? Is it the Doctor?" An older man had followed Donna out of the house and down to the street, a slightly familiar old man who was just missing a red cap and a coat but otherwise looked exactly the same as he had over Christmas years and years ago. Luna could see his connection to Donna in the gold (grandfather, maternal) and saw the coincidence, but there wasn't really such a thing as coincidence when it came to her dad, and there was something more going on that revolved around Donna; it was faint, pulsing and sometimes-there in the gold and it made her worried. Despite the recognition and the camaraderie and the ease of introduction it made her worried.

"What, you've met before?" Donna asked, and the Doctor answered from where he stood out on the street, poking around under the hood of the Nobel's car.

"Christmas Eve."

"He disappeared right in front of me," the old man reminisced. "And there was a girl with him too, pale blonde thing, about up to here..." Luna waved to him quietly, and he grinned back. "Grown up a bit, though." He offered her a hand. "Wilfred Mott. Wilf. Pleasure to meet you."

"Luna," she replied. "I don't think we made it to the pleasantries last time."

"You lot didn't stick around long enough."

"And you never told me?" Donna demanded. Wilf shrugged.

"You never asked." Then, to the Doctor, "So you must be one of those aliens."

"Well, don't go shouting it around." He stood up straight and offered Wilf a hand. "Nice to meet you properly."

Wilf shook it enthusiastically. "A proper alien hand."

"We should let the Colonel know about the Sontarans," Luna said. "Ross can-" But Jenkins was at the far end of the street, on the phone himself. Donna pulled out her mobile.

"Hang on, Martha gave me her number. In case of emergencies or complaints and all that. Let me-" She picked up on the third ring, voice tinny and distorted on the end of the phone. The Doctor moved over, standing next to her.

"Martha? Hold on, he wants to talk to you."

The Doctor took the phone. "Martha? Tell Mace it's Sontarans. Code Red Sontarans. They're in the file. But if they're inside the factory, don't start shooting, UNIT will be massacred. We'll be back as soon as we can. You got that?"

An affirmation on the other end, and then she hung up. The Doctor handed Donna the phone back.

"Now," he said, turning back to the car with sonic in hand. "Let's see what you're hiding."

* * *

"You've been at this for ages," Donna complained from her seat next to Wilf on the curb. "Sonicing it before didn't help, why would it help now?"

"It's only been twenty minutes," Luna said mildly, poking aside a bit of wiring. "And now we know what we're looking for."

"Which is what, exactly?"

She gestured vaguely. "Alien stuff."

The car sparked suddenly, and the Doctor jumped back in surprise. "Ooh, temporal pocket! Ha! I knew there was something there. One second out of sync with real time."

"What's it hiding?"

Approaching footsteps interrupted. "Men and their cars," Sylvia Noble groused at them, coming down the sidewalk. "Sometimes I think if I were a car-" She stopped short, lip twisting in distaste. "Oh, it's you. Doctor- what was it?"

"Yeah, that's me," the Doctor waved, still waving the sonic around under the hood.

Wilf looked back and forth between them. "What, have you met him as well?"

"Dad, he's the man from the wedding! When you were sick with the Spanish Flu. I'm warning you, the last time that man turned up it was a disaster!"

"Yes," Luna agreed. "He rather does tend to make a mess."

"What- who're you?" Sylvia turned to Donna. "Who's she?"

But before Donna could reply the car sparked again and thick, clouds gas began hissing out of the car hood.

"Back, everybody back," the Doctor ordered. He switched sonic frequencies and buzzed at the car. A few moments and many more sparks later the thing spluttered off, leaving the car shrouded behind a screen of smoke.

"That'll stop it," he said. Sylvia gaped at him.

"You've blown up the car! I told you, Dad, he's a nuisance! What sort of Doctor blows up a car?"

"Not now, Mum," Donna grouched. Sylvia turned the brunt of her ire on her.

"Oh, should I make an appointment?"

"I doubt that would help much," Luna said, straight-faced. "He's not very punctual."

"And who are you anyways? What sort of teenager hangs out with madmen like him?"

"I'm his daughter."

Sylvia gaped, gave up and stalked off. Wilf elbowed the Doctor surreptitiously. "So is it aliens?"

"Yes, yes," he waved off. "And that wasn't just exhaust fumes. That was artificial gas."

"Poisonous." Luna added. Because what was the point of mysterious gas in every car in the world if it wasn't poisonous.

"It's not safe," Wilf declared. "I'm gonna get it off the street."

There was a flash of smoke and suffocation and danger and "No, Wilf, don't-" but Luna's warning came too late and the car doors locked themselves on Donna's grandfather before anyone even registered what was happening. All along the street the other cars started hissing, spewing foul, cloudy gas up into the atmosphere. Wilf banged on the glass, Donna cried for help, the Doctor tried to sonic the car open, and nothing helped. Wilf coughed, choked on the gas inside the car, crumpled. In the doorway, Sylvia looked on in panic.

Everyone became shadows in the haze. Luna closed her eyes for barely a moment, sorting through a handful and then a dozen possibilities in a split second before making a decision, knowing how to fix it.

"Break the glass," she said quietly. She could see it in the gold, Sylvia with a hatchet, Donna with a crowbar, Ross' gun, herself with-

"Reducto!"

Glass shattered (and maybe the front fender crumpled a little but who cared) and Donna helped her drag Wilf out, coughing. The Doctor was suddenly standing over them.

"Get inside," he ordered, brushing broken glass off Wilf's sweater. "Get inside and block out as much of the gas as you can, okay?" Behind them Jenkins pulled up in a tiny black cab that had seen better days.

"It's the only thing I could find without ATMOS," he called by way of apology.

"It's perfect," Luna assured him while her father herded Wilf and Sylvia into the house. "I call shotgun."

A minute later they were racing towards UNIT's temporary HQ and no amount of sulking on Donna or the Doctor's part could persuade Luna to change seats with them.

* * *

Yes yes I'm sorry I meant to post this in March (freakin' March yes I know) but things happened and I'm lazy and besides we all know the sequel never lives up to the original.

Reviews are, as always, welcome and are also in fact highly encouraged because it was thanks to a review that y'all are getting this so definitely review.

Also hey what did you guys think of the season finale/this entire season, huh?


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